GB491662A - Improvements in or relating to electromagnetic relays - Google Patents

Abstract

491,662. Light current relays. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., GRAHAM, J. ST.-C. W., and SHARPE, H. D. March 6, 1937, No. 6718. [Class 38 (v)] As shown in Figs. 1 and 3, the operating electromagnet comprises a pair of coils 6 on a U-shaped core 2 the poles of which are below lateral extensions of an armature 7 consisting of a flat blade of springy magnetic material which is clamped at one end to lie along the length of a supporting member 1. The member 1 may, as shown, be the yoke of a standard telephone relay, one end of which is suitably bent. The armature has contacts on opposite sides adapted to engage corresponding contacts on upper and lower relatively rigid springs 9, 10 in the unoperated end operated positions respectively, backing springs 11, 12 being provided to reinforce the springs 9, 10. The core 2 is mounted on but magnetically insulated from the support 1. To secure rapidity of operation the ratio of inductance to resistance is kept low and a considerable proportion of this resistance is made external to the coils by being wound on a china former 15 attached to the member 1, this arrangement additionally providing adequate cooling facilities for the additional resistance.